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201.
202.
Marcelo S Carvalho Maria de Lourdes F Domingues José L Mantovano Euclides Quintino S Filho 《Spectrochimica Acta Part B: Atomic Spectroscopy》1998,53(14):1945-1949
A sensitive method based on the preconcentration of uranium on powdered polyurethane foam (PUF) has been developed to determinate this element in water samples by X-ray florescence. Uranium at ppb levels was sorbed as the salicylate complex on powdered PUF at pH 4.0. The resulting PUF was filtered through a filter paper and used for X-ray fluorescence measurements. For 50 μg/l of uranium the coefficient of variation for five measurements is 5% and the detection limit is 5.5 μg/l. The interference level of various ions and ligands was studied and optimum conditions were developed to determine uranium in reference materials, waste water, mine drainage, and sea water. 相似文献
203.
Dr. Alexandra D. Easley Alison Mangano Prof. Dr. Brett P. Fors 《Angewandte Chemie (International ed. in English)》2023,62(20):e202218062
Polyurethanes (PUs) are a class of materials usually synthesized from isocyanates, diols, and water. Water is essential for producing carbon dioxide (CO2) which is used for the self-blowing of the foams. Due to safety concerns with the production of isocyanates, alternative chemistries have been evaluated and cyclic carbonate systems have shown great promise. In a recent advancement by Bourguignon, Grignard, and Detrembleur, a cyclic carbonate and diamine system is capable of generating CO2 for self-blowing through hydrolysis of the carbonate-based monomer. The authors demonstrate that with a simple variation of the diamine monomer a wide range of physical and thermo-mechanical properties were achievable. This work represents a significant step towards safer and more environmentally friendly PUs. 相似文献